Brass Monkey, a Boston-based startup, is one of the early movers. It has about 20 games on its website, including mini-golf, dodgeball and boat racing, that are in "open beta," meaning anyone can try them. Other entrants include Korea's Entropy Technology, which will launch its first game this month.

The games use the sensors inside iPhones and Android devices to allow players to swing them like a golf club or turn them like a steering wheel. The game itself is displayed on a big screen with a browser, such as on a PC, Mac, or some newer TVs.

Proponents say the games challenge the future of more traditional video games, in which players gather round a console or hunch over a mobile phone. The new games can be played anywhere, as long as there's a Wi-Fi network and a computer to provide the display.

"We're interested in what we call the mid-core market: people who don't necessarily come home and play 'Halo' for four to six hours, but who do want a game more complex than just playing around with 'Tetris,'" said Mike Kanarek, a product manager at Brass Monkey.

How to play

Brass Monkey golf app

To play its games, users download the Brass Monkey app to their phones and then choose a game from its website. The app connects via Wi-Fi to the browser on the PC (or whatever is being used as the main display) and to a server at Brass Monkey, which helps keep all the devices in synch.

Kanarek says smartphones can detect movement as accurately as a Wii controller, though the Wii and Xbox also have an infrared sensor that detects players' movements in the room, giving them an extra data point.

There are a few kinks to work out. Brass Monkey's platform currently uses Flash for the display, which rules out using an iPad instead of a PC or Mac, but an HTML 5 version is in the works. And setting up the games can be a bit complex, though a video explains how it's done.

Brass Monkey isn't interested in developing the games itself; rather, it provides the platform and tools for other developers to use. It plans to make money by collecting a share of revenue from developers, who can charge for games, sell virtual goods or make money in other ways.

"We hope eventually to make the space rich enough that companies like Electronic Arts and Activision will want to get on board," Kanarek said.

Entropy says its golf game, "Let's Motion Golf," will be available for iOS and Android devices next month. It will also be embedded in the latest tablet from Ainol, the Novo Hero II, which is due out this month.

Game consoles aging

Michael Inouye, a senior analyst with ABI Research, says the dominant console makers, Nintendo, Sony and Microsoft, are in their "twilight years," partly because of the rise of mobile gaming.

They will soon strike back, however. Nintendo plans to release its next-generation Wii U in time for the holiday shopping season, while Sony and Microsoft are expected to roll out new consoles next year. And the big console game makers are investing heavily in mobile games.

Microsoft has also released a new app with Windows 8, called SmartGlass, which can turn a user's smartphone or tablet into a second screen where they can control movies and games playing on the big screen.

For now, independent game makers have the lead. But the console world isn't far behind them.